FIGURE 7.

Tracer injections of the non-toxin subunit B of cholera toxin (CtB) within the retrosplenial cortex resulted in dense cell soma label in the ipsilateral claustrum in a distribution that overlapped with claustral (vCLA) parvalbumin (PV) expression (for a comparable case using Fluoro-gold, see Supplementary Figure S4 and for injections sites see Supplementary Figure S5). At anterior-posterior (AP) levels rostral to the anterior horn of the neostriatum (CPu, A–Aⁱⁱ) parvalbumin and CtB label delineated a claustral border (white dashed line) that was horizontally oriented within the arch of the forceps minor of the corpus callosum (fm). At rostral and mid-striatal AP levels (B–Bⁱⁱ,C–Cⁱⁱ, respectively), the claustral border was more vertically oriented alongside the external capsule (ec). acc, nucleus accumbens; CPu, caudate/putamen; ec, external capsule; Ins, insular cortex; Pir, piriform cortex. Scale bar = 200 μm.